In northern Canada, beside the "green" issue of the long term vulnerability of the terrain to road building operations, there is an additional problem that huge areas of ground are so swampy (it's called....um...."muskeg" up here and is everywhere eh!), and lakes and river are so frequent that any low cost road built to a specific mine or similar site is only usable in winter when the ground and lakes freeze solid. With global warming affecting the region more intensely than in more southerly areas, winter freeze-up is becoming increasingly shorter and its duration more unpredictable. Sometimes -- as with the diamond mine complex recently-- important planned transportation schedules are impossible to carry out. Airships offer an obvious temptation in this situation, holding out the prospect of secure availability of summer transport for heavy loads where winter freezes fail, and the huge savings in not having to build and monitor roads in some cases.However, one of the possible problems with blimps and dirigibles that is said to limit their usefulness -- not a negligible one in northern Canada and many other remote locations - is the difficulty and risk in operating them in any kind of extremely windy or stormy weather. This is plausibly less of an issue in freight operations than scheduled passenger transport, but still a constraint. It might might confine dirigibles to warm weather operations -- how long the "season" might be should emerge with experience-- meaning that occasionally, where year-round access was needed, winter-use roads will still have to be built, eliminating some of the ecological benefits.Heavy-lift dirigibles are an idea that keeps coming back around here every twenty or thirty years but never seems to actually prove feasible. Hope it works this time....

Whenever I read an article about the return of airships, I am puzzled that the designers are using helium instead of creating hard-shelled envelops containing a vacuum (the air being pumped out on the ground using relatively cheap landline electricity). The airship's altitude would be controlled by letting in however much air is needed, or -- when greater altitude is required -- pumped out again using pumps aboard the airship. A system like this was patented about 30 years ago by a man named, I believe, Johnson, but as far as I know never built. A vacuum is lighter than helium (or hydrogen), and if the external hardshell as light as the flexible helium envelop would provide more lift. Finally, a vacuum airship should be easier (and cheaper) to fly over long distances and multi-day missions. The problem of sun-heated helium with its expanding envelop during the day and night-cooled helium with reduced lift would be eliminated.
Richard Friedmanfriedman1123@AOL.com

I wonder if the keys to returning the airship to commercial usefulness might be found in Kipling's short story "With the Night Mail" and an article on the building low termperature ionic thrusters which appeared in the Economist several years ago.

The focus of "With the Night Mail" is political, centering on an international body, "The Board of Aerial Control", of which the nationalist in Kipling can not entirely improve. But to make is airships capable carrying enough cargo to effectively compete with sea ships, he imagines a "ray" which safely and cheaply heats the airships gas bags. Of course, he doesn't explain how these rays a generated except to hint that that ray generators made in England are better than those of German make.

A few months after I read "With the Night Mail", The Economist's science section carried an article that reminded me of Kipling rays. Ionic thrusters have mostly used heaters to create the ionized gas to expelled electromagentically. A heaters are heavy and and the ratio of heat used to thrust provided sharly limits the usefulness of ionic thrusters even in deep space.

A researcher was expermenting with a microwave generator to ionize Nitrogen. As I recall, his efforts had produced ions with less energy input and with a less massive device than the typical heater. The experimental ionizer used strongly focused microwaves to get the high levels of ionization needed for a thruster.

But what if the ionizer microwave beams were defocused and sent instead into a large volumn of Nitrogen gas? Would they duplicate the effect of Kipling's magic rays? The microwave heating ought to be safer that flame heating for air filled blimps, although it is unlikely to be cheaper, unless Joepen's suggestion could be used to power the microwave generator.

But by picking the right microwave frequency, the microwave method could be applied to Helium as was. Since hot Helium, at given pressure, is less dense than the gas at ambient temperature, it should take less of the expense Helium to provide the needed lift.

In the early 1970's Boeing proposed a similar blimp device for moving oil in huge bladders over long distances. The objective then was horizontal travel rather than just heavy lift. So both companies have good experience to get this project operational. Once the 100 ton unit is proven, then we know bigger ones will follow.These Sky Cranes will be a valuable tool for use all over the world.

This will be a new factor in the debate over oil and gas exploration in roadless or sensitive areas in the western US. A major point of contention is the damage caused by the dust and vibrations from trucks in the areas. An airlift would eliminate both of these problems.

Measure twice and cut once,sorry to be pedantic, but a helicopter with engines stopped mid-air will simply auto-rotate to the ground. (refer to gyrocopters). the sort of shock-and-awe helicopter accidents with big fireballs, seen on tv, result from a dysfunctioning or jammed rear (directional) rotor, which robs the helicopter the ability from being dragged along by the rotation of its main rotor to spectacular death.

Wouldn't it be better to make it bigger? There are many applications where being able to move a 100 ton object is useful, and there are currently limited means of doing so. Power plant turbines, for example, are more efficient the bigger they are but they are limited by the size of a shaft you can move to the site.

Why? because with the climate in Canada for example, it is the winter that works best as ice roads for heavy trucks can be built on rivers and lakes, but in spring or summer it can be hard to ship in supplies or to send out ore samples and so on.

Also, a helicopter has the gliding capacity of a paperweight. If the engine stops, there is often a tragedy. With thesenew blimps, it stays in the air while the engine is repaired.

I can also see it as great in roadless areas in the tropics where to build a road would be very expensive.

Finally, the big advantage will be in energy costs; the costs per tonne-kilometre will be lower than on barges for three months and ice roads for three months and nothing for the six months of freeze up and break up.

The obnly people I see as unhappy about this development are Bombardier, as they own the "bush" aircraft market right now and Boeing will now be a competitor.

I wish Boeing and its Canadian Airlift partner success and i see it as a project that will work well in Ecuador or Baffin Island.